It is known to isomerize or crack paraffinic, or waxy feeds to produce liquid products in the lubricating oil boiling range. Various catalysts have been used for this purpose, preferred catalysts generally being constituted of Group VIII noble metals composited with an acidic support. Catalytic dewaxing using small pore crystalline zeolites has also been used to remove paraffins, or waxy hydrocarbons from a feed; the waxy components being recovered from the feed via selective adsorption onto the zeolite rather than by chemical conversion. A method using a small pore zeolite catalyst to chemically convert, selectively dewax and recover a paraffinic, or waxy hydrocarbon from a feed however is known, and is disclosed in U.S. Pat. No. 3,684,691.
In accordance with the process disclosed in U.S. Pat. No. 3,684,691, a preheated n-paraffin-containing petroleum feed, and hydrogen, are passed downflow and contacted with a fixed bed of a crystalline alumino-silicate zeolite of average uniform pore size below about 6, particularly from 4 to less than 6 angstrom units, ion-exchanged with either hydrogen or a Group IIB metal, and reacted at conversion conditions to selectively convert the n-paraffins of the feed on entry into the pores to a lower boiling gaseous material which is evolved as an effluent. The more valuable branched and cyclic hydrocarbons, because they are incapable of entering the zeolite pores, are selectively passed downstream with the dewaxed liquid effluent.
In U.S. patent application Ser. No. 343,387, filed Nov. 22, 1994 by Brandes, Zinkie and Alward, now abandoned, of which the present Application is an improvement, there is disclosed a catalyst, and process utilizing this catalyst for the catalytic upgrading of paraffinic, or waxy feeds by selectively dewaxing these materials to produce lube oil products, or lubricants. The catalysts employed in this process are characterized as unitized mixed powder pellet catalysts constituted of both a dewaxing component and an isomerization component. The dewaxing component is a molecular sieve or zeolite of intermediate pore size; specifically, a zeolite having a 10 membered ring unidirectional pore material which has oval 1-D pores having a minor axis between 4.2 .ANG. and 4.8 .ANG. and a major axis between 5.4 .ANG. and 7.0 .ANG. as determined by X-ray crystallography. The dewaxing component is preferably impregnated with at least one Group VIII metal, most preferably a Group VIII noble metal such as platinum or palladium. In the preparation of the catalyst, the zeolite dewaxing component is powdered and mixed with the powdered isomerization catalyst component, characterized as a refractory metal oxide support, e.g., alumina, silica-alumina, zirconia, titanium, etc. on which has been deposited a catalytically active metal, e.g., a Group VIB, VIIB, or Group VIII metal, or mixture thereof, suitably platinum or palladium. This mixture of components is formed into a homogeneous mass, and the mass is compressed, extruded or pelletized to produce the unitized powder pellet catalyst. Whereas, this process and catalyst performs admirably, there nonetheless remains need for further improvements in both the process, and catalyst.